Coal-feeding apparatus for rotary cement-kilns, &amp;c.



WITNESSES //W 70/? H. E. KIEFER.

GOAL FEEDING APPARATUS FOR ROTARY CEMENT KILNS, 6:0. APPLICATION FILED MAY 14, 1910.

993,604. Patented May 30, 1911. I V I I 3;;

M2 I A I 4 9 I J 5 I7 {6 22 24 g;

4 J 7 10 a r: a 2/ as I I] 1 fi LT: "I I I I MANOR/{HS HERMAN E. KIEFER, OF EASTON, PENNSYLVANIA.

GOAL-FEEDING APPARATUS FOR ROTARY CEMENT-KILNS, &o.

l Specification of Letters Patent.

Application filed May 14, 1910. Serial No. 561,302.

Patented May 30, 1911.

To all whom it may concern:

Be it known that I, HERMAN E. KIEFER, a citizen of the United States, residing at Easton, Northampton county, Pennsylvania, have made certain new and useful Inventions Relating to Coal- Feeding Apparatus for Rotary Cement-Kilns, &c., of which the following is a specification, taken in connection with the accompanying drawings, which form part of the same.

This invention relates to rotary'cement kiln apparatus for regularly and reliably feeding powdered coal fuel thereto and also, if desired, for, similarly supplying the raw cement material to the kiln. This feeding apparatus may comprise a primary feeder in the form of a screw cooperating with a secondary screw feeder which may be mounted on the same shaft. The secondary feeder is provided with a plurality of flights so as to form a number of spiral feeding passages between them and the length of this secondary feeder which is mounted between cutoff plates is preferably made radically different from the pitch of its flights or a multiple thereof. The cutoff plates are formed with restricted apertures so that the spiral feeding passage communicating with the inlet aperture in the first plate is closed at its discharge end, While another passage is at that time in communication with the discharge aperture in the other cutoff plate so that it is impossible for the material to force its way or flood through this secondary conveyer and a regular feed of material is thus effected so long as the material is supplied by the primary feeder.

In the illustrative embodiment of this invention. shown in the drawings, Figure 1 is a, vertical section showing a coal and raw material feeder arranged in connection with a rotary cement kiln, Fig. 2 is an enlarged sectional View of the coal feeder therefor, Fig. 3 is a transverse section thereof substantially along the line 3-3 of Fig. 2, and Fig. 4 is a sectional view of a modified form of feeder.

In the illustrative embodiment of the invention shown in Figs. 1 to 3 of the drawings, the rotary kiln 16 is'shown as mounted on suitable hearing rolls 18 which cooperate with the tires 1'." and which may be rotated. at the desired speed to give the proper speed of rotation to the kiln or this may be more positively effected in other ways. The upper end of the kiln may be connected in the blast pipe and nozzle 12 within the injector 31. The powdered coal fuel fed down the-chute 10 is incorporated in the usual way with the impelling jet from the blast nozzle and with other air which may if desired, be admitted through openings in the injector casing, not shown, so as to form the usual fuel jet and discharge the same through the burner tube 13 into the rotary kiln to produce the luminous coal flame therein. The powdered coal may be delivered from time to time to the coal bins 2 which may have any desired form and construction by a suitable coal supply screw 1 or other feeding device, by which a sufficient amount of coal is maintained in the various bins. A suitable feeder casing 7 may be arranged at the bottom of the bin 2 and the opening between the bin and easing controlled by suitable slides such as 3 which allow suflicient coal to fall into the casing.

A primary feeder of screw form may be arranged in this casing to feed forward the coal from the bin. As shown in Figs. 1 and 2, this primary feeder may comprise a shaft 40 on which one or more helical flights 5 are arranged so as to feed the coal forward when the shaft is rotated by the pulley 4 which may of coursebe connected with the usual variable speed operating device. The secondary feeder may, as illustrated, in this instance, be of screw form in which a plurality of flights are mounted or formed on the same shaft 40; four flights 6 having considerably greater diameter than the primary feed screw being illustrated in this instance, although of course, the number of flights may be greater or less, from three to six flights giving excellent results. These spiral flights of the secondary feeder preferably fit quite tightly within the casing 7, the clearance being considerably exaggerated in the drawings for clearness of illustration. The length of this secondary oonveyer is preferably radically different from the pitch length of its flights or any multiple thereof so that for instance this secondary feed screw" may be given a length equal to one.-

half, one and a half or two and ahalf turns of'its fli 'hts. 1

Suitab e cutofi plates such as 8-9 may be mounted at eitherend of the secondary feeder and rovided at their lower portions with constrlcted apertures, cotiperating with only part of the spiral feeding passages between the flights. The cutofl plate 8 may upper part of the cutoff plate so that it could not discharge any material, the longitudinal off plates so secondary conveyer shall have a length of other forms of feeding apparatus. multiple secondary screw feeder with its coclearance being of course verymuch smaller than illustrated so as to give the tightness desired. The angular position of the restricted apertures in the cutoff plates is so arrangedwith respect to the length of the secondary feed screw as to prevent the discharge of material from any of the spiral.

-feeding passages which are simultaneously receiving material through the communicating inlet aperture. It is manifest that this result can be secured by arranging the an'g'ular relation of the apertures'in the two-cutthatit is not necessary that the exactly one and a half turns or the like.-

The' finely powdered coal fuel in the bin '2 will be received and fed forward in the' casing 7 b the primary feed screw 5 so that it will sli e down the inletchannel 4-7 and regularly pass through the inlet aperture 48 in the first cutoff plate 8 so as to enter the spiral feedin passage; which is in alinement therewith. s long as the secondary feed screw rotates the powdered coal is positively and re larly fed through its casing and regular y discharged in small amounts through the outlet passage 49 in the cutofi plate 9 as each of the spiral feeding passages comes into alinement therewith. These small amounts of powdered coal fall down the chute 10 andare engaged by the initial air jet and blown into the kiln in the usual way. If, however; the coal feeder is stopped it is impossible with such a secondary feeder for the powdered coal to continue to force its way or flood through the feeder into the injector which sometimes occurs to an undesirable and even dangerous extent with some This v operating cutofi plates also tends to prevent any excessive feed of coal to the injector 01 kiln when coal is supplied to the tank or mary feeder may be used in connection with such a secondary cutofi' multiple screw feeder and it is also unnecessary that the secondary feeder shall be of different diameter than the primary feeder where both are of the screw type. Such feeders may of course also be used to uniformly feed other materials in powdered condition and give desirable results when operating on the finely powdered cement material used in the dry process of making Portland cement. As

illustrated in Fig. 4, a single flight feed screw 32 is mounted on the shaft a0 so as to feed such material as powdered coal or raw cement material from the bin 2 along the casin 33 and through the aperture48 in the type, fourflights 35 being indicated, and the secondary feeder having a length of two and a half turns, although as previously. indicated, any other uneven number of turns cuto plate 38. The secondary feeder is in Y may be used such. for instance as approximately a 'halfturn or one and a half turn lengths. The material is uniformly discharged through the outlet aperture 49 in the cutoff plate 39 so as to descend the. chute 10 and it is of course understood that the secondary feeder should fit quite tightly within its casing andcutofl' plates, considerably less clearance ,than indicated being desirable and the'tightness of fit being dependent on the material opera-ted on and the closeness of regulation desired.

In order to secure'most efiicient operation it is desirable-t0 feed the. coal fuel to a rotarykiln in a, positive and regular manner and alsoto effect a similarly reliable feed 7 of the raw material to the kiln. In this way uniformity of the combustion and heating conditions can be maintained and fuel economized as Well as Lminimizing danger of' I overheating the kilnlining or producing underburned and unreliable cement clinker. For these reasons itis desirable to have a similarly effective feeding device to control the feed of raw cement material which because ofits finely powdered condition is also hard to handle and feed. The raw material bin 27 may, as illustrated, be supplied with material from time to time by the material supply screw 28. A suitable slide 26 may be arranged at the bottom of this bin to determine the accesslof material to the feedmason multiple screw secondary feeder 22*of the type illustrated in greater detail in Fig. 2.

This secondary fwder 22 receives the mate- I feed the desired" amount of material to the devices so that it will vary in conformity 'kiln from time to time'and the coal feed is of course adjusted correspondingly to give the best results. Also, if desired, the speed of kiln rotation may be effected by connected with the amount of raw material and fuel fed thereto. I 7

Having described this invention in connection with a number of illustrative. embodiments, proportions, parts and arrangements, to the details of which disclosure the invention is not of course to be limited, what is claimed as new is 1. In rotary kiln feeding "apparatus, :a

rotary cement kiln, a coal bin and communieating casing, a chute connected with the discharge end of said casing, an injector and burner tube connected with said chute to discharge into thenkiln, a feeder shaft mounted within said casing, a rimary screw feeder mounted on said shaft to feed the powdered coal delivered from said bin, a secondary four-flight feed screw of greater diameter than said. prima feed screw mounted on said shaft and having a length approximately equal to one and a half of its turns and cutoff plates provided with restricted apertures at their lower portions mounted within said casin with both ends of said secon ary feed'screw and prevent flooding therethrough.

2. In rotary kiln feeding apparatus, a

rotary cement kiln, a coal bin and communieating casing, an injector device connected with the 'dischar e end of said casing and with said kiln, a eeder shaft mounted with in said casing, a primary. screw feeder mounted on said shaft to feed forward the powdered coal delivered from said bin, a secondary multiple flight feed screw of greater diameter than said primary feed screw mounted on said shaft and having a length approximately equal to one and a hal of its turns and cutoff plates provided,

.with restricted apertures mounted within said casin -to' e06 erate with both ends of said secon ary fee screw and prevent flooding therethrough.

3. In rotary kiln feeding apparatus, a rotary cement kiln, a coal bin and communicating casing, an injector device connected to cotiperate "with said "casing and discharging into said kiln, a'primary screw feeder '-in said casing to feed along the "same the material from said bin, at secondary multiple flight feed screw having a length approximately equal to one and a half its turns and cutoff plates provided with restricted apertures in their lower portions mounted within said casing to coiiperate with both ends of said secondary feed screw, and prevent flooding therethrough.

4, n furnace feeding apparatus, a furnace, a fuelbin and connected casing, an injector device connected with said casing and discharging into said furnace, a primary feeder mounted in said casing, a secondary multiple flight feed screw having a correspondm number of spiral feeding passages mounte in said casing to receive the fuel fed by said primary feeder and cutoff plates provided with restricted apertures mounted within said casing to coiipe'rate' with both ends of said secondary feed screw and cut off the discharge of the material from the feeding passages which are in communication with the inlet aperture.

5. In furnace feeding apparatus, a furnace,- a fuel bin and communicating casing, an injectmg device connected with said cas ing, and discharging into said furnace, a

primary feeder, a secondary multiple feed screw having a plurality of spiral feeding assa es mounte in said casing to receive' uel rom said primary feeder and cutoff plates provided with restricted apertures mounte within said casin to cotiperate with both ends of said secon ary feed screw and prevent material passing through said spira feeding passage independent of the movement of said secondary feed screw.

6. In furnace feeding apparatus, a bin and communicating casin a primary feeder to feed material from said bin, a secondary multiple flight feed screw having a pluralityof spiral feeding passages mounted in said casing to receive material from said primary feeder, a cutoff plate having an in let aperture mounted in said casing at the inlet end of said secondary feed screw and a cutoff plate having a restricted outlet aperture mounted at the discharge end of said secondary feed screw to prevent discharge 'of material from any spiral feeding pas- '8. In feeding apparatus, a. casing, aprimary feeder in said casing, a secondary multiple flight feed screw having a plu.

rality of spiral feeding passages mounted in, an enlarged portion'of said casing and cutofl plates provided with restricted apertures in said casing, cooperating with both ends of said secondary feed screw to prevent the discharge of material from any feeding passage thereof which is simultaneously receiving material. a

9; In feeding apparatus, a casing, a primary feed screw in said casing, a secondary multiple flight feed screw having a plur'ality of spiral feeding passages mounted in said casing and having .a larger diameter than said primary feed screw, a cutoff plate having a restricted inlet aperture mounted to cooperate with'the inlet end of said secondary feed screw, there being anin'clined inlet channel leading from. said primary eeaeoa feed screw to said inlet aperture and a cut- 10. In feeding apparatus, a casing, a shaft mounted in said casmg, a primary feed screw on said shaft, a secondary feed screw having a plurality of spiral feeding passages mounted on sand shaft, a cutoff plate having a restricted inlet aperture cooperating with the inlet end of said secondary feed screw and a cutofi plate having a restricted outle't aperture cooperating with the discharge end of said secondary feed screw to prevent the simultaneous discharge of material from any feeding passage-which is in communica-- tion with said inlet aperture.

HERMAN E. KIEFER,

' Witnesses:

R. B. SMITH, O. S. UNAUGST. 

